You probably know sea stars as starfish, the name sea stars are commonly known by. But sea stars aren’t really fish. Sea stars, like sea urchins and sand dollars, do not have backbones, which makes them part of a group called invertebrates. Fish have backbones, which makes them vertebrates. Got it?
There are more than 1,600 species (types) of sea stars living in all the world’s oceans. Sea stars occupy every type of habitat, including tidal pools, rocky shores, sea grass, kelp beds, and coral reefs. Some sea stars even live in sands as deep as 20,530 feet (9,000 meters).
Most sea stars sport spiny skin and five arms, although some can grow as many as 50 arms. The arms are covered with pincer-like organs and suckers that allow the animal to slowly creep along the ocean floor.
